1. Field of the Invention
This invention relates to a vertical type conveyor provided with a frame, a plurality of belt pulleys rotatably supported by the frame, and first and second endless conveyor belts traveling around the plurality of belt pulleys and defining an abutment area in which the first and second conveyor belts are in contact with and confront each other, wherein the load to be conveyed is held between both the belts so that the load can be conveyed in the vertical direction.
2. Description of the Prior Art
Vertical type conveyors for carrying a load to be conveyed, such as granulated substances, i.e., concrete, cement, lime, ores, fertilizer, grains or slurry in the vertical direction, are known. For example, the conveyor comprises a supplying portion set up on the lower part, a vertical conveying portion, and a discharging portion provided above the vertical conveying portion. The conveyor also comprises a rigid frame and a plurality of rollers, a hopper, a shoot and a drive mounted on the frame. Namely, whole members of the conveyor are mounted on the frame, and the frame is designed according to the specification as to lifting height, conveying length and other considerations.
In the vertical conveying portion, a plurality of supporting rollers as back-up rollers or bearing rollers are disposed in zigzags. These supporting rollers are rototably supported by the frame. The supporting rollers act for increasing the supporting force for holding the load between belts and changing the supporting force according to the loose fitting state of the belts between which load is inserted. By giving a force to the belts, which are in contact with and confront each other in the vertical conveying portion, conveying of the load is smoothly carried out and the load is prevented from falling. Maintenance of the supporting rollers is usually carried out by workers.
In Japanese Patent Publication (KOKAI) 14806/1985 (Showa 60), a conveyor for conveying a load in inclined directions is disclosed, which comprises bearing rollers rototably mounted to a frame through a bracket, supporting levers having supporting rods connected with the bearing rollers in which one end is hinged to the frame, while the other end is connected to a weight and ropes wound on a pulley of a supporting lever for transmitting tension by weight to the supporting lever.
In a conveyor for conveying a load in an inclined direction, supporting or bearing rollers are attached at given intervals on the frame of the vertical conveying portion. Therefore, when maintenance on the supporting rollers is carried out, it is necessary that workers ascend and descend the frame to approach the supporting rollers for maintenance, consequently a great deal of labor is required for maintenance.
Further, to carry out the above-mentioned maintenance, plural corridors and stairs should be mounted to the frame at given intervals of height. Therefore, the number of members of the conveyor is increased by the members for the corridors and stairs, the strength of the frame itself should be increased in order to secure the members for the corridors and stairs to the frame.
Further, there is no freedom against changes in lifting height, since the frame is formed at a height according to the lifting height of the conveyor.
Further, the above-mentioned conveyor is designed one by one to meet the specification and the nature of the load to be conveyed. Therefore, even when taking the increase in common parts into consideration, to lower the cost of such a device is limited.